In many fields of modern medicine, in particular in the field of cardiology, imaging methods are increasingly being used in minor and more complex clinical procedures.
The imaging methods are basically used firstly for orientation in the body structure during the operative procedure and secondly to locate medical instruments, which are required within the framework of the operative procedure (such as a catheter in the case of heart surgery, or surgical instruments), in exactly the correct position. Another example is the exact positioning of an aortic valve prosthesis in a cardiological operation. These methods are also used in diagnostics, moreover.
The imaging methods can be classed in different categories. Thus, on the one hand there is two-dimensional imaging. These modalities acquire two-dimensional images. This includes fluoroscopy which, for example, produces a continuous film of two-dimensional X-ray images in real time.
A further category relates to three-dimensional imaging to generate three-dimensional images. This includes, for example, C-arm CTC-arm CT. This method involves rotational angiography with three-dimensional image reconstruction during the intervention on X-ray C-arms. Other examples of three-dimensional imaging methods are known in the prior art (for example CT, MR, etc.).
In addition to the above classification into two-dimensional and three-dimensional imaging methods, these methods may also be categorized according to the degree of resolution. There are therefore high-resolution methods and less high-resolution methods. The high-resolution methods are distinguished by a very high level of detail. These methods are conventionally static, however, and during an operation do not provide the operator or examiner with any information about the respective body structures being examined in relation to time. Movement information cannot be derived from the static images therefore. The static imaging methods are conventionally used pre-operatively.
In addition to the static methods there are the dynamic imaging methods which include a time reference. These methods include, for example, ultrasound, in particular cardiac ultrasound, optical methods (for example methods in which a camera is introduced into an organ in order to acquire images), infrared techniques and radioscopy. It is likewise possible to generate dynamic images using magnetic resonance tomographs and computed tomographs.
The need for high-resolution real-time methods for three-dimensional imaging is growing constantly in the field of interventional medicine. Procedures with this requirement, such as a transfemoral aortic valve replacement, are increasingly being carried out in particular in the field of cardiology. Atrial fibrillation has been treated with the aid of sclerotherapy procedures within the left atrium for a relatively long time already in the field of electrophysiology.
That the imaging is either not dynamic (for example C-arm CTC-arm CT) or that the imaging does not reproduce the current state of the patient (for example computed tomography), or that the acquired images do not have the required spatial resolution (such as ultrasound, electro-anatomical mapping, etc.), or that they do not generally provide three-dimensional images has proven to be problematic in the known imaging methods.